Deputy U.S. Marshal Matt Westover two years ago submitted a DNA profile to a public registry, the same one that many people use in their family genealogical research. But the Omaha law enforcement officer wasn’t looking for some long-lost relative — at least not his own. The DNA profile he submitted in 2020 came from the brother of William Leslie Arnold, the fugitive who killed his parents in Omaha in 1958, buried them in the backyard, nine years later escaped from the Nebraska Penitentiary and vanished without a trace.